Preparation and Improved Friction and Wear Performance of the Nano-MoSi2 Coating on Ni Substrate by Plasma Spraying

In this work, the wear performance of nano- and ordinary MoSi 2 plasma-sprayed coating on Ni substrate are compared. MoSi 2 nanopowder is prepared by ball milling followed by heat treatment processes. Atmospheric plasma spraying with argon atmosphere protection has been used to deposit the powders onto the nickel substrate. Ni substrate, MoSi 2 coating, and nano-MoSi 2 coating were subjected to reciprocating wear test. Wear tests were done on a pin on plate machine by sliding MoSi 2 coating and substrates without coating against 52100 steel as the pin, at a temperature of 27 °C in dry condition. A friction coefficient of 0.18 ± 0.1 is obtained for nanostructured MoSi 2 coating, whereas a friction coefficient of 0.2 ± 0.1 is obtained for conventional MoSi 2 coating under normal load of 20 N. Wear performance of nanostructured MoSi 2 coating was better as compared to the conventional MoSi 2 coating. The three observed dominant types of wear mechanisms were adhesive, oxidation and abrasive. Morphologies and phases of coating, wear tracks, wear debris and counterpart steel pins were evaluated by SEM with EDS and X-ray diffraction. The microhardness and adhesion strength of nanostructured MoSi 2 coating are determined by 1000 HV and 27 MPa, respectively. Graphic Abstract